effects of aerobic exercise versus weight training in breast cancer survivors during chemotherapy

Conditions: Breast Neoplasms

Summary: the purpose of this study is to compare the effects of two different types of exercise, aerobic exercise training (aet) and resistance exercise training (ret), on quality of life (qol) in early stage breast cancer survivors receiving chemotherapy. it is hypothesized that both aet and ret would have beneficial effects on qol.

the study was a prospective, three-armed, randomized controlled trial. participants were stratified by site (edmonton, ottawa, and vancouver) and planned chemotherapy protocol (taxane-based versus nontaxane-based) and randomly assigned to aet, ret, or usual care (uc) in a 1:1:1 ratio using a random-numbers table. participants assigned to the aet group were asked to perform aerobic exercise three times per week on a recumbent or upright cycle ergometer, treadmill, or elliptical. exercise duration began at 15 minutes for weeks 0 through 2, and then systematically increased by 5 minutes every three weeks thereafter to 45 minutes for weeks 18 and beyond. exercise intensity began at 60% of vo2max for weeks 0 through 2 and then systematically increased by 10% every 6 weeks thereafter to 80% of vo2max for weeks 12 and beyond. warm-up and cool-down periods consisted of 5 minutes of aerobic activity at the power output of the ventilatory equivalent for oxygen (approximately 50% of peak oxygen consumption). participants assigned to the ret group were asked to perform resistance exercise three times per week, which consisted of two sets of 10 repetitions of 9 different exercises performed at 60-70% of 1-repetition maximum. the specific exercises were: leg extension, leg curl, calf raises, chest press, latissimus pulldown, overhead press, triceps extension, biceps curls, and modified curl-ups. resistance was increased by approximately 10% or the next weight level when the participant was able to complete 12 repetitions per set without difficulty.

Eligibility criteria:
inclusion criteria: * breast cancer early stage i -iiia * completed axillary surgery * scheduled to receive adjuvant chemotherapy for 9 - 24 weeks * approval of the treating oncologist * able to understand and provide written informed consent in english or french (ottawa) * 18+ years of age * no uncontrolled hypertension, cardiac illness, psychiatric condition * no contraindication to exercise as determined by a fitness test exclusion criteria: * pregnant. * unwilling to accept randomization. * any medical condition that would be a contraindication to exercise. the clinicians will make this decision. * unwilling to travel to/participate in the exercise program as defined by the protocol. * previous chemotherapy (previous cancer is not an exclusion criteria). * cancer recurrence. * planned/known absence of greater than 2 weeks during the intended study period. * previous therapy for known breast cancer. * those who have had tram (i.e., transabdominal rectus abdominus muscle reconstructive surgery) done. * moderate lymphedema (\>20% or \>200ml difference between the affected arm and the unaffected arm).

Keywords: aerobic exercise weight lifting breast cancer quality of life